The development of endoscopic ureteroscopy has allowed for the treatment of ureteral and renal pelvis diseases such as nephrolithiasis, ureteral stricture, uretero-pelvic junction obstruction and upper tract transitional cell carcinoma, through a minimally invasive approach. Ureteroscopy is generally performed in the operating room under general anesthesia. Typically, a cysto scope is inserted into the bladder and the ureteral orifice is identified in order to gain access to the upper urinary tract. The inner diameter of the ureter generally measures approximately 3 mm. The ureteral orifice is accessed using flexible wires which can be passed up into the renal pelvis. A ureteroscope can then be passed over the wire and guided up the ureter to the renal pelvis. This may be accomplished under direct visualization or with fluoroscopic guidance.
Due to the size restraints of accessing the upper urinary tract, ureteroscope size has been limited to 8 French or approximately 3 mm in outside diameter. A ureteroscope typically includes three channels, including an optical channel for endoscope imaging (−1 mm diameter); a fiber light source (−0.5 mm diameter), and a working channel for laser fiber insertion and irrigation. After accounting for the required optics and light source, a flexible ureteroscope allows for only a single working channel of approximately 1 mm. Unfortunately, this single working channel must accommodate irrigation to allow for visibility and the passage of a laser fiber in order to either destroy kidney stone or ablate tissue. The size of the working channel poses limitations to the treatment of upper urinary tract disease. The passage of the laser fiber through the small working channel severely impedes irrigation flow and thus limits visibility. Additionally, the passage of a semi-stiff laser fiber inhibits deflection of the tip of the ureteroscope and thus limits the ability to treat all areas of the urinary collecting system.
Conventional uteroscopes require passing a laser fiber through the working channel which impedes irrigation flow and deflection of the ureteroscope tip. To counteract lower irrigation flows, high pressure irrigation has been utilized. However, visualization can still be affected. Smaller flexible holmium laser fibers (200 micron) have been utilized. However, these fibers still affect deflection and irrigant flow and are fragile. Given the confines of the upper urinary tract system and limitations to current technologies, there exists a clinical need for a novel system to access the entire upper urinary tract that allows improved irrigation flow, a larger working channel, and unimpeded tip deflection to access difficult areas of the renal pelvis.